SimLife was an old school game made by maxis, the people who created SimCity and SimEarth. It was designed to be an artificial intelligence type replication of evolution and ecology. It was slow and buggy, and wasnt a very realistic simulation of ecology because it was so simple (basically everything eventually evolved to be an asexual filter feeder which had 8 offspring, the maximum number possible, with the shortest gestation period. All the plants turned into small asexual weeds with drifting seeds) Nevertheless, it was a fun game to play with, mostly to watch the animals you make eat each other, mate, etc...